/*
 * SPDX-License-Identifier: Apache-2.0
 *
 * The OpenSearch Contributors require contributions made to
 * this file be licensed under the Apache-2.0 license or a
 * compatible open source license.
 */

/*
 * Licensed to Elasticsearch under one or more contributor
 * license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright
 * ownership. Elasticsearch licenses this file to you under
 * the Apache License, Version 2.0 (the "License"); you may
 * not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

/*
 * Modifications Copyright OpenSearch Contributors. See
 * GitHub history for details.
 */

package org.opensearch.upgrades;

import org.apache.http.util.EntityUtils;
import org.opensearch.LegacyESVersion;
import org.opensearch.Version;
import org.opensearch.client.Request;
import org.opensearch.client.Response;
import org.opensearch.client.ResponseException;
import org.opensearch.client.RestClient;
import org.opensearch.cluster.metadata.IndexMetadata;
import org.opensearch.cluster.metadata.MetadataIndexStateService;
import org.opensearch.common.Booleans;
import org.opensearch.common.CheckedFunction;
import org.opensearch.common.Strings;
import org.opensearch.common.settings.Settings;
import org.opensearch.common.xcontent.XContentBuilder;
import org.opensearch.common.xcontent.json.JsonXContent;
import org.opensearch.common.xcontent.support.XContentMapValues;
import org.opensearch.index.IndexSettings;
import org.opensearch.test.NotEqualMessageBuilder;
import org.opensearch.test.XContentTestUtils;
import org.opensearch.test.rest.OpenSearchRestTestCase;
import org.opensearch.test.rest.yaml.ObjectPath;
import org.junit.Before;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Base64;
import java.util.Collection;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Set;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import static java.util.Collections.emptyMap;
import static java.util.Collections.singletonList;
import static java.util.Collections.singletonMap;
import static org.opensearch.cluster.metadata.IndexNameExpressionResolver.SYSTEM_INDEX_ENFORCEMENT_VERSION;
import static org.opensearch.cluster.routing.UnassignedInfo.INDEX_DELAYED_NODE_LEFT_TIMEOUT_SETTING;
import static org.opensearch.cluster.routing.allocation.decider.MaxRetryAllocationDecider.SETTING_ALLOCATION_MAX_RETRY;
import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
import static org.hamcrest.Matchers.containsString;
import static org.hamcrest.Matchers.equalTo;
import static org.hamcrest.Matchers.greaterThan;
import static org.hamcrest.Matchers.greaterThanOrEqualTo;
import static org.hamcrest.Matchers.hasKey;
import static org.hamcrest.Matchers.hasSize;
import static org.hamcrest.Matchers.is;
import static org.hamcrest.Matchers.notNullValue;
import static org.hamcrest.Matchers.nullValue;

/**
 * Tests to run before and after a full cluster restart. This is run twice,
 * one with {@code tests.is_old_cluster} set to {@code true} against a cluster
 * of an older version. The cluster is shutdown and a cluster of the new
 * version is started with the same data directories and then this is rerun
 * with {@code tests.is_old_cluster} set to {@code false}.
 */
public class FullClusterRestartIT extends AbstractFullClusterRestartTestCase {

    private String index;
    private String type;

    @Before
    public void setIndex() {
        index = getTestName().toLowerCase(Locale.ROOT);
    }

    @Before
    public void setType() {
        type = "_doc";
    }

    public void testSearch() throws Exception {
        int count;
        if (isRunningAgainstOldCluster()) {
            XContentBuilder mappingsAndSettings = jsonBuilder();
            mappingsAndSettings.startObject();
            {
                mappingsAndSettings.startObject("settings");
                mappingsAndSettings.field("number_of_shards", 1);
                mappingsAndSettings.field("number_of_replicas", 0);
                mappingsAndSettings.endObject();
            }
            {
                mappingsAndSettings.startObject("mappings");
                if (isRunningAgainstAncientCluster()) {
                    mappingsAndSettings.startObject(type);
                }
                mappingsAndSettings.startObject("properties");
                {
                    mappingsAndSettings.startObject("string");
                    mappingsAndSettings.field("type", "text");
                    mappingsAndSettings.endObject();
                }
                {
                    mappingsAndSettings.startObject("dots_in_field_names");
                    mappingsAndSettings.field("type", "text");
                    mappingsAndSettings.endObject();
                }
                {
                    mappingsAndSettings.startObject("binary");
                    mappingsAndSettings.field("type", "binary");
                    mappingsAndSettings.field("store", "true");
                    mappingsAndSettings.endObject();
                }
                mappingsAndSettings.endObject();
                if (isRunningAgainstAncientCluster()) {
                    mappingsAndSettings.endObject();
                }
                mappingsAndSettings.endObject();
            }
            mappingsAndSettings.endObject();

            Request createIndex = new Request("PUT", "/" + index);
            createIndex.setJsonEntity(Strings.toString(mappingsAndSettings));
            createIndex.setOptions(allowTypesRemovalWarnings());
            client().performRequest(createIndex);

            count = randomIntBetween(2000, 3000);
            byte[] randomByteArray = new byte[16];
            random().nextBytes(randomByteArray);
            indexRandomDocuments(
                    count,
                    true,
                    true,
                    randomBoolean(),
                    i -> JsonXContent.contentBuilder().startObject()
                            .field("string", randomAlphaOfLength(10))
                            .field("int", randomInt(100))
                            .field("float", randomFloat())
                            // be sure to create a "proper" boolean (True, False) for the first document so that automapping is correct
                            .field("bool", i > 0 && randomBoolean())
                            .field("field.with.dots", randomAlphaOfLength(10))
                            .field("binary", Base64.getEncoder().encodeToString(randomByteArray))
                            .endObject()
            );
            refresh();
        } else {
            count = countOfIndexedRandomDocuments();
        }

        ensureGreenLongWait(index);
        assertBasicSearchWorks(count);
        assertAllSearchWorks(count);
        assertBasicAggregationWorks();
        assertRealtimeGetWorks();
        assertStoredBinaryFields(count);
    }

    public void testNewReplicasWork() throws Exception {
        if (isRunningAgainstOldCluster()) {
            XContentBuilder mappingsAndSettings = jsonBuilder();
            mappingsAndSettings.startObject();
            {
                mappingsAndSettings.startObject("settings");
                mappingsAndSettings.field("number_of_shards", 1);
                mappingsAndSettings.field("number_of_replicas", 0);
                mappingsAndSettings.endObject();
            }
            {
                mappingsAndSettings.startObject("mappings");
                mappingsAndSettings.startObject("properties");
                {
                    mappingsAndSettings.startObject("field");
                    mappingsAndSettings.field("type", "text");
                    mappingsAndSettings.endObject();
                }
                mappingsAndSettings.endObject();
                mappingsAndSettings.endObject();
            }
            mappingsAndSettings.endObject();

            Request createIndex = new Request("PUT", "/" + index);
            createIndex.setJsonEntity(Strings.toString(mappingsAndSettings));
            client().performRequest(createIndex);

            int numDocs = randomIntBetween(2000, 3000);
            indexRandomDocuments(
                    numDocs, true, false, randomBoolean(), i -> JsonXContent.contentBuilder().startObject().field("field", "value").endObject());
            logger.info("Refreshing [{}]", index);
            client().performRequest(new Request("POST", "/" + index + "/_refresh"));
        } else {
            final int numReplicas = 1;
            final long startTime = System.currentTimeMillis();
            logger.debug("--> creating [{}] replicas for index [{}]", numReplicas, index);
            Request setNumberOfReplicas = new Request("PUT", "/" + index + "/_settings");
            setNumberOfReplicas.setJsonEntity("{ \"index\": { \"number_of_replicas\" : " + numReplicas + " }}");
            client().performRequest(setNumberOfReplicas);

            ensureGreenLongWait(index);

            logger.debug("--> index [{}] is green, took [{}] ms", index, (System.currentTimeMillis() - startTime));
            Map<String, Object> recoverRsp = entityAsMap(client().performRequest(new Request("GET", "/" + index + "/_recovery")));
            logger.debug("--> recovery status:\n{}", recoverRsp);

            Set<Integer> counts = new HashSet<>();
            for (String node : dataNodes(index, client())) {
                Request search = new Request("GET", "/" + index + "/_search");
                search.addParameter("preference", "_only_nodes:" + node);
                Map<String, Object> responseBody = entityAsMap(client().performRequest(search));
                assertNoFailures(responseBody);
                int hits = extractTotalHits(responseBody);
                counts.add(hits);
            }
            assertEquals("All nodes should have a consistent number of documents", 1, counts.size());
        }
    }

    public void testClusterState() throws Exception {
        if (isRunningAgainstOldCluster()) {
            XContentBuilder mappingsAndSettings = jsonBuilder();
            mappingsAndSettings.startObject();
            mappingsAndSettings.field("index_patterns", index);
            mappingsAndSettings.field("order", "1000");
            {
                mappingsAndSettings.startObject("settings");
                mappingsAndSettings.field("number_of_shards", 1);
                mappingsAndSettings.field("number_of_replicas", 0);
                mappingsAndSettings.endObject();
            }
            mappingsAndSettings.endObject();
            Request createTemplate = new Request("PUT", "/_template/template_1");
            createTemplate.setJsonEntity(Strings.toString(mappingsAndSettings));
            client().performRequest(createTemplate);
            client().performRequest(new Request("PUT", "/" + index));
        }

        // verifying if we can still read some properties from cluster state api:
        Map<String, Object> clusterState = entityAsMap(client().performRequest(new Request("GET", "/_cluster/state")));

        // Check some global properties:
        String numberOfShards = (String) XContentMapValues.extractValue(
            "metadata.templates.template_1.settings.index.number_of_shards", clusterState);
        assertEquals("1", numberOfShards);
        String numberOfReplicas = (String) XContentMapValues.extractValue(
            "metadata.templates.template_1.settings.index.number_of_replicas", clusterState);
        assertEquals("0", numberOfReplicas);

        // Check some index properties:
        numberOfShards = (String) XContentMapValues.extractValue("metadata.indices." + index +
            ".settings.index.number_of_shards", clusterState);
        assertEquals("1", numberOfShards);
        numberOfReplicas = (String) XContentMapValues.extractValue("metadata.indices." + index +
                ".settings.index.number_of_replicas", clusterState);
        assertEquals("0", numberOfReplicas);
        Version version = Version.fromId(Integer.valueOf((String) XContentMapValues.extractValue("metadata.indices." + index +
            ".settings.index.version.created", clusterState)));
        assertEquals(getOldClusterVersion(), version);

    }

    public void testShrink() throws IOException {
        String shrunkenIndex = index + "_shrunk";
        int numDocs;
        if (isRunningAgainstOldCluster()) {
            XContentBuilder mappingsAndSettings = jsonBuilder();
            mappingsAndSettings.startObject();
            {
                mappingsAndSettings.startObject("mappings");
                {
                    mappingsAndSettings.startObject("properties");
                    {
                        mappingsAndSettings.startObject("field");
                        {
                            mappingsAndSettings.field("type", "text");
                        }
                        mappingsAndSettings.endObject();
                    }
                    mappingsAndSettings.endObject();
                }
                mappingsAndSettings.endObject();
                mappingsAndSettings.startObject("settings");
                {
                    mappingsAndSettings.field("index.number_of_shards", 5);
                }
                mappingsAndSettings.endObject();
            }
            mappingsAndSettings.endObject();

            Request createIndex = new Request("PUT", "/" + index);
            createIndex.setJsonEntity(Strings.toString(mappingsAndSettings));
            client().performRequest(createIndex);

            numDocs = randomIntBetween(512, 1024);
            indexRandomDocuments(
                    numDocs, true, true, randomBoolean(), i -> JsonXContent.contentBuilder().startObject().field("field", "value").endObject());

            ensureGreen(index); // wait for source index to be available on both nodes before starting shrink

            Request updateSettingsRequest = new Request("PUT", "/" + index + "/_settings");
            updateSettingsRequest.setJsonEntity("{\"settings\": {\"index.blocks.write\": true}}");
            client().performRequest(updateSettingsRequest);

            Request shrinkIndexRequest = new Request("PUT", "/" + index + "/_shrink/" + shrunkenIndex);
            if (getOldClusterVersion().before(LegacyESVersion.V_7_0_0)) {
                shrinkIndexRequest.addParameter("copy_settings", "true");
            }
            shrinkIndexRequest.setJsonEntity("{\"settings\": {\"index.number_of_shards\": 1}}");
            client().performRequest(shrinkIndexRequest);

            refreshAllIndices();
        } else {
            numDocs = countOfIndexedRandomDocuments();
        }

        Map<?, ?> response = entityAsMap(client().performRequest(new Request("GET", "/" + index + "/_search")));
        assertNoFailures(response);
        int totalShards = (int) XContentMapValues.extractValue("_shards.total", response);
        assertThat(totalShards, greaterThan(1));
        int successfulShards = (int) XContentMapValues.extractValue("_shards.successful", response);
        assertEquals(totalShards, successfulShards);
        int totalHits = extractTotalHits(response);
        assertEquals(numDocs, totalHits);

        response = entityAsMap(client().performRequest(new Request("GET", "/" + shrunkenIndex+ "/_search")));
        assertNoFailures(response);
        totalShards = (int) XContentMapValues.extractValue("_shards.total", response);
        assertEquals(1, totalShards);
        successfulShards = (int) XContentMapValues.extractValue("_shards.successful", response);
        assertEquals(1, successfulShards);
        totalHits = extractTotalHits(response);
        assertEquals(numDocs, totalHits);
    }

    public void testShrinkAfterUpgrade() throws IOException {
        String shrunkenIndex = index + "_shrunk";
        int numDocs;
        if (isRunningAgainstOldCluster()) {
            XContentBuilder mappingsAndSettings = jsonBuilder();
            mappingsAndSettings.startObject();
            {
                mappingsAndSettings.startObject("mappings");
                {
                    mappingsAndSettings.startObject("properties");
                    {
                        mappingsAndSettings.startObject("field");
                        {
                            mappingsAndSettings.field("type", "text");
                        }
                        mappingsAndSettings.endObject();
                    }
                    mappingsAndSettings.endObject();
                }
                mappingsAndSettings.endObject();
                // the default number of shards is now one so we have to set the number of shards to be more than one explicitly
                mappingsAndSettings.startObject("settings");
                mappingsAndSettings.field("index.number_of_shards", 5);
                mappingsAndSettings.endObject();
            }
            mappingsAndSettings.endObject();

            Request createIndex = new Request("PUT", "/" + index);
            createIndex.setJsonEntity(Strings.toString(mappingsAndSettings));
            client().performRequest(createIndex);

            numDocs = randomIntBetween(512, 1024);
            indexRandomDocuments(
                    numDocs,
                    true,
                    true,
                    randomBoolean(),
                    i -> JsonXContent.contentBuilder().startObject().field("field", "value").endObject()
            );
        } else {
            ensureGreen(index); // wait for source index to be available on both nodes before starting shrink

            Request updateSettingsRequest = new Request("PUT", "/" + index + "/_settings");
            updateSettingsRequest.setJsonEntity("{\"settings\": {\"index.blocks.write\": true}}");
            client().performRequest(updateSettingsRequest);

            Request shrinkIndexRequest = new Request("PUT", "/" + index + "/_shrink/" + shrunkenIndex);
            shrinkIndexRequest.setJsonEntity("{\"settings\": {\"index.number_of_shards\": 1}}");
            client().performRequest(shrinkIndexRequest);

            numDocs = countOfIndexedRandomDocuments();
        }

        refreshAllIndices();

        Map<?, ?> response = entityAsMap(client().performRequest(new Request("GET", "/" + index + "/_search")));
        assertNoFailures(response);
        int totalShards = (int) XContentMapValues.extractValue("_shards.total", response);
        assertThat(totalShards, greaterThan(1));
        int successfulShards = (int) XContentMapValues.extractValue("_shards.successful", response);
        assertEquals(totalShards, successfulShards);
        int totalHits = extractTotalHits(response);
        assertEquals(numDocs, totalHits);

        if (isRunningAgainstOldCluster() == false) {
            response = entityAsMap(client().performRequest(new Request("GET", "/" + shrunkenIndex + "/_search")));
            assertNoFailures(response);
            totalShards = (int) XContentMapValues.extractValue("_shards.total", response);
            assertEquals(1, totalShards);
            successfulShards = (int) XContentMapValues.extractValue("_shards.successful", response);
            assertEquals(1, successfulShards);
            totalHits = extractTotalHits(response);
            assertEquals(numDocs, totalHits);
        }
    }

    /**
     * Test upgrading after a rollover. Specifically:
     * <ol>
     *  <li>Create an index with a write alias
     *  <li>Write some documents to the write alias
     *  <li>Roll over the index
     *  <li>Make sure the document count is correct
     *  <li>Upgrade
     *  <li>Write some more documents to the write alias
     *  <li>Make sure the document count is correct
     * </ol>
     */
    public void testRollover() throws IOException {
        if (isRunningAgainstOldCluster()) {
            Request createIndex = new Request("PUT", "/" + index + "-000001");
            createIndex.setJsonEntity("{"
                    + "  \"aliases\": {"
                    + "    \"" + index + "_write\": {}"
                    + "  }"
                    + "}");
            client().performRequest(createIndex);
        }

        int bulkCount = 10;
        StringBuilder bulk = new StringBuilder();
        for (int i = 0; i < bulkCount; i++) {
            bulk.append("{\"index\":{}}\n");
            bulk.append("{\"test\":\"test\"}\n");
        }
        Request bulkRequest = new Request("POST", "/" + index + "_write/_bulk");
        bulkRequest.setJsonEntity(bulk.toString());
        bulkRequest.addParameter("refresh", "");
        assertThat(EntityUtils.toString(client().performRequest(bulkRequest).getEntity()), containsString("\"errors\":false"));

        if (isRunningAgainstOldCluster()) {
            Request rolloverRequest = new Request("POST", "/" + index + "_write/_rollover");
            rolloverRequest.setJsonEntity("{"
                    + "  \"conditions\": {"
                    + "    \"max_docs\": 5"
                    + "  }"
                    + "}");
            client().performRequest(rolloverRequest);

            assertThat(EntityUtils.toString(client().performRequest(new Request("GET", "/_cat/indices?v")).getEntity()),
                    containsString("testrollover-000002"));
        }

        Request countRequest = new Request("POST", "/" + index + "-*/_search");
        countRequest.addParameter("size", "0");
        Map<String, Object> count = entityAsMap(client().performRequest(countRequest));
        assertNoFailures(count);

        int expectedCount = bulkCount + (isRunningAgainstOldCluster() ? 0 : bulkCount);
        assertEquals(expectedCount, extractTotalHits(count));
    }

    void assertBasicSearchWorks(int count) throws IOException {
        logger.info("--> testing basic search");
        {
            Map<String, Object> response = entityAsMap(client().performRequest(new Request("GET", "/" + index + "/_search")));
            assertNoFailures(response);
            int numDocs = extractTotalHits(response);
            logger.info("Found {} in old index", numDocs);
            assertEquals(count, numDocs);
        }

        logger.info("--> testing basic search with sort");
        {
            Request searchRequest = new Request("GET", "/" + index + "/_search");
            searchRequest.setJsonEntity("{ \"sort\": [{ \"int\" : \"asc\" }]}");
            Map<String, Object> response = entityAsMap(client().performRequest(searchRequest));
            assertNoFailures(response);
            assertTotalHits(count, response);
        }

        logger.info("--> testing exists filter");
        {
            Request searchRequest = new Request("GET", "/" + index + "/_search");
            searchRequest.setJsonEntity("{ \"query\": { \"exists\" : {\"field\": \"string\"} }}");
            Map<String, Object> response = entityAsMap(client().performRequest(searchRequest));
            assertNoFailures(response);
            assertTotalHits(count, response);
        }

        logger.info("--> testing field with dots in the name");
        {
            Request searchRequest = new Request("GET", "/" + index + "/_search");
            searchRequest.setJsonEntity("{ \"query\": { \"exists\" : {\"field\": \"field.with.dots\"} }}");
            Map<String, Object> response = entityAsMap(client().performRequest(searchRequest));
            assertNoFailures(response);
            assertTotalHits(count, response);
        }
    }

    void assertAllSearchWorks(int count) throws IOException {
        logger.info("--> testing _all search");
        Map<String, Object> response = entityAsMap(client().performRequest(new Request("GET", "/" + index + "/_search")));
        assertNoFailures(response);
        assertTotalHits(count, response);
        Map<?, ?> bestHit = (Map<?, ?>) ((List<?>) (XContentMapValues.extractValue("hits.hits", response))).get(0);

        // Make sure there are payloads and they are taken into account for the score
        // the 'string' field has a boost of 4 in the mappings so it should get a payload boost
        String stringValue = (String) XContentMapValues.extractValue("_source.string", bestHit);
        assertNotNull(stringValue);
        String id = (String) bestHit.get("_id");

        Request explainRequest = new Request("GET", "/" + index + "/_explain" + "/" + id);
        explainRequest.setJsonEntity("{ \"query\": { \"match_all\" : {} }}");
        String explanation = toStr(client().performRequest(explainRequest));
        assertFalse("Could not find payload boost in explanation\n" + explanation, explanation.contains("payloadBoost"));

        // Make sure the query can run on the whole index
        Request searchRequest = new Request("GET", "/" + index + "/_search");
        searchRequest.setEntity(explainRequest.getEntity());
        searchRequest.addParameter("explain", "true");
        Map<?, ?> matchAllResponse = entityAsMap(client().performRequest(searchRequest));
        assertNoFailures(matchAllResponse);
        assertTotalHits(count, matchAllResponse);
    }

    void assertBasicAggregationWorks() throws IOException {
        // histogram on a long
        Request longHistogramRequest = new Request("GET", "/" + index + "/_search");
        longHistogramRequest.setJsonEntity("{ \"aggs\": { \"histo\" : {\"histogram\" : {\"field\": \"int\", \"interval\": 10}} }}");
        Map<?, ?> longHistogram = entityAsMap(client().performRequest(longHistogramRequest));
        assertNoFailures(longHistogram);
        List<?> histoBuckets = (List<?>) XContentMapValues.extractValue("aggregations.histo.buckets", longHistogram);
        int histoCount = 0;
        for (Object entry : histoBuckets) {
            Map<?, ?> bucket = (Map<?, ?>) entry;
            histoCount += (Integer) bucket.get("doc_count");
        }
        assertTotalHits(histoCount, longHistogram);

        // terms on a boolean
        Request boolTermsRequest = new Request("GET", "/" + index + "/_search");
        boolTermsRequest.setJsonEntity("{ \"aggs\": { \"bool_terms\" : {\"terms\" : {\"field\": \"bool\"}} }}");
        Map<?, ?> boolTerms = entityAsMap(client().performRequest(boolTermsRequest));
        List<?> termsBuckets = (List<?>) XContentMapValues.extractValue("aggregations.bool_terms.buckets", boolTerms);
        int termsCount = 0;
        for (Object entry : termsBuckets) {
            Map<?, ?> bucket = (Map<?, ?>) entry;
            termsCount += (Integer) bucket.get("doc_count");
        }
        assertTotalHits(termsCount, boolTerms);
    }

    void assertRealtimeGetWorks() throws IOException {
        Request disableAutoRefresh = new Request("PUT", "/" + index + "/_settings");
        disableAutoRefresh.setJsonEntity("{ \"index\": { \"refresh_interval\" : -1 }}");
        client().performRequest(disableAutoRefresh);

        Request searchRequest = new Request("GET", "/" + index + "/_search");
        searchRequest.setJsonEntity("{ \"query\": { \"match_all\" : {} }}");
        Map<?, ?> searchResponse = entityAsMap(client().performRequest(searchRequest));
        Map<?, ?> hit = (Map<?, ?>) ((List<?>)(XContentMapValues.extractValue("hits.hits", searchResponse))).get(0);
        String docId = (String) hit.get("_id");

        Request updateRequest = new Request("POST", "/" + index + "/_update/" + docId);
        updateRequest.setJsonEntity("{ \"doc\" : { \"foo\": \"bar\"}}");
        client().performRequest(updateRequest);

        Request getRequest = new Request("GET", "/" + index + "/" + type + "/" + docId);
        Map<String, Object> getRsp = entityAsMap(client().performRequest(getRequest));
        Map<?, ?> source = (Map<?, ?>) getRsp.get("_source");
        assertTrue("doc does not contain 'foo' key: " + source, source.containsKey("foo"));

        Request enableAutoRefresh = new Request("PUT", "/" + index + "/_settings");
        enableAutoRefresh.setJsonEntity("{ \"index\": { \"refresh_interval\" : \"1s\" }}");
        client().performRequest(enableAutoRefresh);
    }

    void assertStoredBinaryFields(int count) throws Exception {
        Request request = new Request("GET", "/" + index + "/_search");
        request.setJsonEntity("{ \"query\": { \"match_all\" : {} }, \"size\": 100, \"stored_fields\": \"binary\"}");
        Map<String, Object> rsp = entityAsMap(client().performRequest(request));

        assertTotalHits(count, rsp);
        List<?> hits = (List<?>) XContentMapValues.extractValue("hits.hits", rsp);
        assertEquals(100, hits.size());
        for (Object hit : hits) {
            Map<?, ?> hitRsp = (Map<?, ?>) hit;
            List<?> values = (List<?>) XContentMapValues.extractValue("fields.binary", hitRsp);
            assertEquals(1, values.size());
            String value = (String) values.get(0);
            byte[] binaryValue = Base64.getDecoder().decode(value);
            assertEquals("Unexpected string length [" + value + "]", 16, binaryValue.length);
        }
    }

    static String toStr(Response response) throws IOException {
        return EntityUtils.toString(response.getEntity());
    }

    /**
     * Tests that a single document survives. Super basic smoke test.
     */
    public void testSingleDoc() throws IOException {
        String docLocation = "/" + index + "/" + type + "/1";
        String doc = "{\"test\": \"test\"}";

        if (isRunningAgainstOldCluster()) {
            Request createDoc = new Request("PUT", docLocation);
            createDoc.setJsonEntity(doc);
            client().performRequest(createDoc);
        }


        Request request = new Request("GET", docLocation);
        assertThat(toStr(client().performRequest(request)), containsString(doc));
    }

    /**
     * Tests that a single empty shard index is correctly recovered. Empty shards are often an edge case.
     */
    public void testEmptyShard() throws IOException {
        final String index = "test_empty_shard";

        if (isRunningAgainstOldCluster()) {
            Settings.Builder settings = Settings.builder()
                .put(IndexMetadata.INDEX_NUMBER_OF_SHARDS_SETTING.getKey(), 1)
                .put(IndexMetadata.INDEX_NUMBER_OF_REPLICAS_SETTING.getKey(), 1)
                // if the node with the replica is the first to be restarted, while a replica is still recovering
                // then delayed allocation will kick in. When the node comes back, the cluster-manager will search for a copy
                // but the recovering copy will be seen as invalid and the cluster health won't return to GREEN
                // before timing out
                .put(INDEX_DELAYED_NODE_LEFT_TIMEOUT_SETTING.getKey(), "100ms")
                .put(SETTING_ALLOCATION_MAX_RETRY.getKey(), "0"); // fail faster
            createIndex(index, settings.build());
        }
        ensureGreen(index);
    }


    /**
     * Tests recovery of an index with or without a translog and the
     * statistics we gather about that.
     */
    public void testRecovery() throws Exception {
        int count;
        boolean shouldHaveTranslog;
        if (isRunningAgainstOldCluster()) {
            count = between(200, 300);
            /* We've had bugs in the past where we couldn't restore
             * an index without a translog so we randomize whether
             * or not we have one. */
            shouldHaveTranslog = randomBoolean();
            Settings.Builder settings = Settings.builder();
            if (minimumNodeVersion().before(Version.V_2_0_0) && randomBoolean()) {
                settings.put(IndexSettings.INDEX_SOFT_DELETES_SETTING.getKey(), randomBoolean());
            }
            final String mappings = randomBoolean() ? "\"_source\": { \"enabled\": false}" : null;
            createIndex(index, settings.build(), mappings);
            indexRandomDocuments(count, true, true, true, i -> jsonBuilder().startObject().field("field", "value").endObject());

            // make sure all recoveries are done
            ensureGreen(index);

            // Force flush so we're sure that all translog are committed
            Request flushRequest = new Request("POST", "/" + index + "/_flush");
            flushRequest.addParameter("force", "true");
            flushRequest.addParameter("wait_if_ongoing", "true");
            assertOK(client().performRequest(flushRequest));

            if (shouldHaveTranslog) {
                // Update a few documents so we are sure to have a translog
                indexRandomDocuments(
                    count / 10,
                    false, // flushing here would invalidate the whole thing
                    false,
                    true,
                    i -> jsonBuilder().startObject().field("field", "value").endObject()
                );
            }
            saveInfoDocument(index + "_should_have_translog", Boolean.toString(shouldHaveTranslog));
        } else {
            count = countOfIndexedRandomDocuments();
            shouldHaveTranslog = Booleans.parseBoolean(loadInfoDocument(index + "_should_have_translog"));
        }

        // Count the documents in the index to make sure we have as many as we put there
        Request countRequest = new Request("GET", "/" + index + "/_search");
        countRequest.addParameter("size", "0");
        refreshAllIndices();
        Map<String, Object> countResponse = entityAsMap(client().performRequest(countRequest));
        assertTotalHits(count, countResponse);

        if (false == isRunningAgainstOldCluster()) {
            boolean restoredFromTranslog = false;
            boolean foundPrimary = false;
            Request recoveryRequest = new Request("GET", "/_cat/recovery/" + index);
            recoveryRequest.addParameter("h", "index,shard,type,stage,translog_ops_recovered");
            recoveryRequest.addParameter("s", "index,shard,type");
            String recoveryResponse = toStr(client().performRequest(recoveryRequest));
            for (String line : recoveryResponse.split("\n")) {
                // Find the primaries
                foundPrimary = true;
                if (false == line.contains("done") && line.contains("existing_store")) {
                    continue;
                }
                /* Mark if we see a primary that looked like it restored from the translog.
                 * Not all primaries will look like this all the time because we modify
                 * random documents when we want there to be a translog and they might
                 * not be spread around all the shards. */
                Matcher m = Pattern.compile("(\\d+)$").matcher(line);
                assertTrue(line, m.find());
                int translogOps = Integer.parseInt(m.group(1));
                if (translogOps > 0) {
                    restoredFromTranslog = true;
                }
            }
            assertTrue("expected to find a primary but didn't\n" + recoveryResponse, foundPrimary);
            assertEquals("mismatch while checking for translog recovery\n" + recoveryResponse, shouldHaveTranslog, restoredFromTranslog);

            String currentLuceneVersion = Version.CURRENT.luceneVersion.toString();
            String bwcLuceneVersion = getOldClusterVersion().luceneVersion.toString();
            String minCompatibleBWCVersion = Version.CURRENT.minimumCompatibilityVersion().luceneVersion.toString();
            if (shouldHaveTranslog && false == currentLuceneVersion.equals(bwcLuceneVersion)) {
                int numCurrentVersion = 0;
                int numBwcVersion = 0;
                Request segmentsRequest = new Request("GET", "/_cat/segments/" + index);
                segmentsRequest.addParameter("h", "prirep,shard,index,version");
                segmentsRequest.addParameter("s", "prirep,shard,index");
                String segmentsResponse = toStr(client().performRequest(segmentsRequest));
                for (String line : segmentsResponse.split("\n")) {
                    if (false == line.startsWith("p")) {
                        continue;
                    }
                    Matcher m = Pattern.compile("(\\d+\\.\\d+\\.\\d+)$").matcher(line);
                    assertTrue(line, m.find());
                    String version = m.group(1);
                    if (currentLuceneVersion.equals(version)) {
                        numCurrentVersion++;
                    } else if (bwcLuceneVersion.equals(version)) {
                        numBwcVersion++;
                    } else if (minCompatibleBWCVersion.equals(version) && minCompatibleBWCVersion.equals(bwcLuceneVersion) == false) {
                        // Our upgrade path from 7.non-last always goes through 7.last, which depending on timing can create 7.last
                        // index segment. We ignore those.
                        continue;
                    } else {
                        fail("expected version to be one of [" + currentLuceneVersion + "," + bwcLuceneVersion + "] but was " + line);
                    }
                }
                assertNotEquals("expected at least 1 current segment after translog recovery. segments:\n" + segmentsResponse,
                    0, numCurrentVersion);
                assertNotEquals("expected at least 1 old segment. segments:\n" + segmentsResponse, 0, numBwcVersion);
            }
        }
    }

    /**
     * Tests snapshot/restore by creating a snapshot and restoring it. It takes
     * a snapshot on the old cluster and restores it on the old cluster as a
     * sanity check and on the new cluster as an upgrade test. It also takes a
     * snapshot on the new cluster and restores that on the new cluster as a
     * test that the repository is ok with containing snapshot from both the
     * old and new versions. All of the snapshots include an index, a template,
     * and some routing configuration.
     */
    public void testSnapshotRestore() throws IOException {
        int count;
        if (isRunningAgainstOldCluster()) {
            // Create the index
            count = between(200, 300);
            Settings.Builder settings = Settings.builder();
            if (minimumNodeVersion().before(Version.V_2_0_0) && randomBoolean()) {
                settings.put(IndexSettings.INDEX_SOFT_DELETES_SETTING.getKey(), randomBoolean());
            }
            createIndex(index, settings.build());
            indexRandomDocuments(count, true, true, randomBoolean(), i -> jsonBuilder().startObject().field("field", "value").endObject());
        } else {
            count = countOfIndexedRandomDocuments();
        }

        // Refresh the index so the count doesn't fail
        refresh();

        // Count the documents in the index to make sure we have as many as we put there
        Request countRequest = new Request("GET", "/" + index + "/_search");
        countRequest.addParameter("size", "0");
        Map<String, Object> countResponse = entityAsMap(client().performRequest(countRequest));
        assertTotalHits(count, countResponse);

        // Stick a routing attribute into to cluster settings so we can see it after the restore
        Request addRoutingSettings = new Request("PUT", "/_cluster/settings");
        addRoutingSettings.setJsonEntity(
                    "{\"persistent\": {\"cluster.routing.allocation.exclude.test_attr\": \"" + getOldClusterVersion() + "\"}}");
        client().performRequest(addRoutingSettings);

        // Stick a template into the cluster so we can see it after the restore
        XContentBuilder templateBuilder = JsonXContent.contentBuilder().startObject();
        templateBuilder.field("index_patterns", "evil_*"); // Don't confuse other tests by applying the template
        templateBuilder.startObject("settings"); {
            templateBuilder.field("number_of_shards", 1);
        }
        templateBuilder.endObject();
        templateBuilder.startObject("mappings"); {
            {
                templateBuilder.startObject("_source");
                {
                    templateBuilder.field("enabled", true);
                }
                templateBuilder.endObject();
            }
        }
        templateBuilder.endObject();
        templateBuilder.startObject("aliases"); {
            templateBuilder.startObject("alias1").endObject();
            templateBuilder.startObject("alias2"); {
                templateBuilder.startObject("filter"); {
                    templateBuilder.startObject("term"); {
                        templateBuilder.field("version", isRunningAgainstOldCluster() ? getOldClusterVersion() : Version.CURRENT);
                    }
                    templateBuilder.endObject();
                }
                templateBuilder.endObject();
            }
            templateBuilder.endObject();
        }
        templateBuilder.endObject().endObject();
        Request createTemplateRequest = new Request("PUT", "/_template/test_template");
        createTemplateRequest.setJsonEntity(Strings.toString(templateBuilder));

        client().performRequest(createTemplateRequest);

        if (isRunningAgainstOldCluster()) {
            // Create the repo
            XContentBuilder repoConfig = JsonXContent.contentBuilder().startObject(); {
                repoConfig.field("type", "fs");
                repoConfig.startObject("settings"); {
                    repoConfig.field("compress", randomBoolean());
                    repoConfig.field("location", System.getProperty("tests.path.repo"));
                }
                repoConfig.endObject();
            }
            repoConfig.endObject();
            Request createRepoRequest = new Request("PUT", "/_snapshot/repo");
            createRepoRequest.setJsonEntity(Strings.toString(repoConfig));
            client().performRequest(createRepoRequest);
        }

        Request createSnapshot = new Request("PUT", "/_snapshot/repo/" + (isRunningAgainstOldCluster() ? "old_snap" : "new_snap"));
        createSnapshot.addParameter("wait_for_completion", "true");
        createSnapshot.setJsonEntity("{\"indices\": \"" + index + "\"}");
        client().performRequest(createSnapshot);

        checkSnapshot("old_snap", count, getOldClusterVersion());
        if (false == isRunningAgainstOldCluster()) {
            checkSnapshot("new_snap", count, Version.CURRENT);
        }
    }

    public void testHistoryUUIDIsAdded() throws Exception {
        if (isRunningAgainstOldCluster()) {
            XContentBuilder mappingsAndSettings = jsonBuilder();
            mappingsAndSettings.startObject();
            {
                mappingsAndSettings.startObject("settings");
                mappingsAndSettings.field("number_of_shards", 1);
                mappingsAndSettings.field("number_of_replicas", 1);
                mappingsAndSettings.endObject();
            }
            mappingsAndSettings.endObject();
            Request createIndex = new Request("PUT", "/" + index);
            createIndex.setJsonEntity(Strings.toString(mappingsAndSettings));
            client().performRequest(createIndex);
        } else {
            ensureGreenLongWait(index);

            Request statsRequest = new Request("GET", index + "/_stats");
            statsRequest.addParameter("level", "shards");
            Response response = client().performRequest(statsRequest);
            List<Object> shardStats = ObjectPath.createFromResponse(response).evaluate("indices." + index + ".shards.0");
            assertThat(shardStats, notNullValue());
            assertThat("Expected stats for 2 shards", shardStats, hasSize(2));
            String globalHistoryUUID = null;
            for (Object shard : shardStats) {
                final String nodeId = ObjectPath.evaluate(shard, "routing.node");
                final Boolean primary = ObjectPath.evaluate(shard, "routing.primary");
                logger.info("evaluating: {} , {}", ObjectPath.evaluate(shard, "routing"), ObjectPath.evaluate(shard, "commit"));
                String historyUUID = ObjectPath.evaluate(shard, "commit.user_data.history_uuid");
                assertThat("no history uuid found on " + nodeId + " (primary: " + primary + ")", historyUUID, notNullValue());
                if (globalHistoryUUID == null) {
                    globalHistoryUUID = historyUUID;
                } else {
                    assertThat("history uuid mismatch on " + nodeId + " (primary: " + primary + ")", historyUUID,
                        equalTo(globalHistoryUUID));
                }
            }
        }
    }

    public void testSoftDeletes() throws Exception {
        if (isRunningAgainstOldCluster()) {
            XContentBuilder mappingsAndSettings = jsonBuilder();
            mappingsAndSettings.startObject();
            {
                mappingsAndSettings.startObject("settings");
                mappingsAndSettings.field("number_of_shards", 1);
                mappingsAndSettings.field("number_of_replicas", 1);
                if (randomBoolean()) {
                    mappingsAndSettings.field("soft_deletes.enabled", true);
                }
                mappingsAndSettings.endObject();
            }
            mappingsAndSettings.endObject();
            Request createIndex = new Request("PUT", "/" + index);
            createIndex.setJsonEntity(Strings.toString(mappingsAndSettings));
            client().performRequest(createIndex);
            int numDocs = between(10, 100);
            for (int i = 0; i < numDocs; i++) {
                String doc = Strings.toString(JsonXContent.contentBuilder().startObject().field("field", "v1").endObject());
                Request request = new Request("POST", "/" + index + "/_doc/" + i);
                request.setJsonEntity(doc);
                client().performRequest(request);
                refreshAllIndices();
            }
            client().performRequest(new Request("POST", "/" + index + "/_flush"));
            int liveDocs = numDocs;
            assertTotalHits(liveDocs, entityAsMap(client().performRequest(new Request("GET", "/" + index + "/_search"))));
            for (int i = 0; i < numDocs; i++) {
                if (randomBoolean()) {
                    String doc = Strings.toString(JsonXContent.contentBuilder().startObject().field("field", "v2").endObject());
                    Request request = new Request("POST", "/" + index + "/_doc/" + i);
                    request.setJsonEntity(doc);
                    client().performRequest(request);
                } else if (randomBoolean()) {
                    client().performRequest(new Request("DELETE", "/" + index + "/_doc/" + i));
                    liveDocs--;
                }
            }
            refreshAllIndices();
            assertTotalHits(liveDocs, entityAsMap(client().performRequest(new Request("GET", "/" + index + "/_search"))));
            saveInfoDocument(index + "_doc_count", Integer.toString(liveDocs));
        } else {
            int liveDocs = Integer.parseInt(loadInfoDocument(index + "_doc_count"));
            assertTotalHits(liveDocs, entityAsMap(client().performRequest(new Request("GET", "/" + index + "/_search"))));
        }
    }

    /**
     * This test creates an index in the old cluster and then closes it. When the cluster is fully restarted in a newer version,
     * it verifies that the index exists and is replicated if the old version supports replication.
     */
    public void testClosedIndices() throws Exception {
        if (isRunningAgainstOldCluster()) {
            createIndex(index, Settings.builder()
                .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 1)
                .build());
            ensureGreen(index);

            int numDocs = 0;
            if (randomBoolean()) {
                numDocs = between(1, 100);
                for (int i = 0; i < numDocs; i++) {
                    final Request request = new Request("POST", "/" + index + "/" + type + "/" + i);
                    request.setJsonEntity(Strings.toString(JsonXContent.contentBuilder().startObject().field("field", "v1").endObject()));
                    assertOK(client().performRequest(request));
                    if (rarely()) {
                        refresh();
                    }
                }
                refresh();
            }

            assertTotalHits(numDocs, entityAsMap(client().performRequest(new Request("GET", "/" + index + "/_search"))));
            saveInfoDocument(index + "_doc_count", Integer.toString(numDocs));
            closeIndex(index);
        }

        if (getOldClusterVersion().onOrAfter(LegacyESVersion.V_7_2_0)) {
            ensureGreenLongWait(index);
            assertClosedIndex(index, true);
        } else {
            assertClosedIndex(index, false);
        }

        if (isRunningAgainstOldCluster() == false) {
            openIndex(index);
            ensureGreen(index);

            final int expectedNumDocs = Integer.parseInt(loadInfoDocument(index + "_doc_count"));
            assertTotalHits(expectedNumDocs, entityAsMap(client().performRequest(new Request("GET", "/" + index + "/_search"))));
        }
    }

    /**
     * Asserts that an index is closed in the cluster state. If `checkRoutingTable` is true, it also asserts
     * that the index has started shards.
     */
    @SuppressWarnings("unchecked")
    private void assertClosedIndex(final String index, final boolean checkRoutingTable) throws IOException {
        final Map<String, ?> state = entityAsMap(client().performRequest(new Request("GET", "/_cluster/state")));

        final Map<String, ?> metadata = (Map<String, Object>) XContentMapValues.extractValue("metadata.indices." + index, state);
        assertThat(metadata, notNullValue());
        assertThat(metadata.get("state"), equalTo("close"));

        final Map<String, ?> blocks = (Map<String, Object>) XContentMapValues.extractValue("blocks.indices." + index, state);
        assertThat(blocks, notNullValue());
        assertThat(blocks.containsKey(String.valueOf(MetadataIndexStateService.INDEX_CLOSED_BLOCK_ID)), is(true));

        final Map<String, ?> settings = (Map<String, Object>) XContentMapValues.extractValue("settings", metadata);
        assertThat(settings, notNullValue());

        final Map<String, ?> routingTable = (Map<String, Object>) XContentMapValues.extractValue("routing_table.indices." + index, state);
        if (checkRoutingTable) {
            assertThat(routingTable, notNullValue());
            assertThat(Booleans.parseBoolean((String) XContentMapValues.extractValue("index.verified_before_close", settings)), is(true));
            final String numberOfShards = (String) XContentMapValues.extractValue("index.number_of_shards", settings);
            assertThat(numberOfShards, notNullValue());
            final int nbShards = Integer.parseInt(numberOfShards);
            assertThat(nbShards, greaterThanOrEqualTo(1));

            for (int i = 0; i < nbShards; i++) {
                final Collection<Map<String, ?>> shards =
                    (Collection<Map<String, ?>>) XContentMapValues.extractValue("shards." + i, routingTable);
                assertThat(shards, notNullValue());
                assertThat(shards.size(), equalTo(2));
                for (Map<String, ?> shard : shards) {
                    assertThat(XContentMapValues.extractValue("shard", shard), equalTo(i));
                    assertThat(XContentMapValues.extractValue("state", shard), equalTo("STARTED"));
                    assertThat(XContentMapValues.extractValue("index", shard), equalTo(index));
                }
            }
        } else {
            assertThat(routingTable, nullValue());
            assertThat(XContentMapValues.extractValue("index.verified_before_close", settings), nullValue());
        }
    }

    private void checkSnapshot(final String snapshotName, final int count, final Version tookOnVersion) throws IOException {
        // Check the snapshot metadata, especially the version
        Request listSnapshotRequest = new Request("GET", "/_snapshot/repo/" + snapshotName);
        Map<String, Object> listSnapshotResponse = entityAsMap(client().performRequest(listSnapshotRequest));
        assertEquals(singletonList(snapshotName), XContentMapValues.extractValue("snapshots.snapshot", listSnapshotResponse));
        assertEquals(singletonList("SUCCESS"), XContentMapValues.extractValue("snapshots.state", listSnapshotResponse));
        assertEquals(singletonList(tookOnVersion.toString()), XContentMapValues.extractValue("snapshots.version", listSnapshotResponse));

        // Remove the routing setting and template so we can test restoring them.
        Request clearRoutingFromSettings = new Request("PUT", "/_cluster/settings");
        clearRoutingFromSettings.setJsonEntity("{\"persistent\":{\"cluster.routing.allocation.exclude.test_attr\": null}}");
        client().performRequest(clearRoutingFromSettings);
        client().performRequest(new Request("DELETE", "/_template/test_template"));

        // Restore
        XContentBuilder restoreCommand = JsonXContent.contentBuilder().startObject();
        restoreCommand.field("include_global_state", true);
        restoreCommand.field("indices", index);
        restoreCommand.field("rename_pattern", index);
        restoreCommand.field("rename_replacement", "restored_" + index);
        restoreCommand.endObject();
        Request restoreRequest = new Request("POST", "/_snapshot/repo/" + snapshotName + "/_restore");
        restoreRequest.addParameter("wait_for_completion", "true");
        restoreRequest.setJsonEntity(Strings.toString(restoreCommand));
        client().performRequest(restoreRequest);

        // Make sure search finds all documents
        Request countRequest = new Request("GET", "/restored_" + index + "/_search");
        countRequest.addParameter("size", "0");
        Map<String, Object> countResponse = entityAsMap(client().performRequest(countRequest));
        assertTotalHits(count, countResponse);

        // Add some extra documents to the index to be sure we can still write to it after restoring it
        int extras = between(1, 100);
        StringBuilder bulk = new StringBuilder();
        for (int i = 0; i < extras; i++) {
            bulk.append("{\"index\":{\"_id\":\"").append(count + i).append("\"}}\n");
            bulk.append("{\"test\":\"test\"}\n");
        }
        Request writeToRestoredRequest = new Request("POST", "/restored_" + index + "/_bulk");
        writeToRestoredRequest.addParameter("refresh", "true");
        writeToRestoredRequest.setJsonEntity(bulk.toString());
        assertThat(EntityUtils.toString(client().performRequest(writeToRestoredRequest).getEntity()), containsString("\"errors\":false"));

        // And count to make sure the add worked
        // Make sure search finds all documents
        Request countAfterWriteRequest = new Request("GET", "/restored_" + index + "/_search");
        countAfterWriteRequest.addParameter("size", "0");
        Map<String, Object> countAfterResponse = entityAsMap(client().performRequest(countRequest));
        assertTotalHits(count + extras, countAfterResponse);

        // Clean up the index for the next iteration
        client().performRequest(new Request("DELETE", "/restored_*"));

        // Check settings added by the restore process
        Request clusterSettingsRequest = new Request("GET", "/_cluster/settings");
        clusterSettingsRequest.addParameter("flat_settings", "true");
        Map<String, Object> clusterSettingsResponse = entityAsMap(client().performRequest(clusterSettingsRequest));
        @SuppressWarnings("unchecked") final Map<String, Object> persistentSettings =
            (Map<String, Object>) clusterSettingsResponse.get("persistent");
        assertThat(persistentSettings.get("cluster.routing.allocation.exclude.test_attr"), equalTo(getOldClusterVersion().toString()));

        // Check that the template was restored successfully
        Request getTemplateRequest = new Request("GET", "/_template/test_template");

        Map<String, Object> getTemplateResponse = entityAsMap(client().performRequest(getTemplateRequest));
        Map<String, Object> expectedTemplate = new HashMap<>();
        expectedTemplate.put("index_patterns", singletonList("evil_*"));
        expectedTemplate.put("settings", singletonMap("index", singletonMap("number_of_shards", "1")));
        expectedTemplate.put("mappings", singletonMap("_source", singletonMap("enabled", true)));

        expectedTemplate.put("order", 0);
        Map<String, Object> aliases = new HashMap<>();
        aliases.put("alias1", emptyMap());
        aliases.put("alias2", singletonMap("filter", singletonMap("term", singletonMap("version", tookOnVersion.toString()))));
        expectedTemplate.put("aliases", aliases);
        expectedTemplate = singletonMap("test_template", expectedTemplate);
        if (false == expectedTemplate.equals(getTemplateResponse)) {
            NotEqualMessageBuilder builder = new NotEqualMessageBuilder();
            builder.compareMaps(getTemplateResponse, expectedTemplate);
            logger.info("expected: {}\nactual:{}", expectedTemplate, getTemplateResponse);
            fail("template doesn't match:\n" + builder.toString());
        }
    }

    // TODO tests for upgrades after shrink. We've had trouble with shrink in the past.

    private void indexRandomDocuments(
        final int count,
        final boolean flushAllowed,
        final boolean saveInfo,
        final boolean specifyId,
        final CheckedFunction<Integer, XContentBuilder, IOException> docSupplier
    ) throws IOException {
        logger.info("Indexing {} random documents", count);
        for (int i = 0; i < count; i++) {
            logger.debug("Indexing document [{}]", i);
            Request createDocument = new Request("POST", "/" + index + "/_doc/" + (specifyId ? i : ""));
            createDocument.setJsonEntity(Strings.toString(docSupplier.apply(i)));
            client().performRequest(createDocument);
            if (rarely()) {
                refreshAllIndices();
            }
            if (flushAllowed && rarely()) {
                logger.debug("Flushing [{}]", index);
                client().performRequest(new Request("POST", "/" + index + "/_flush"));
            }
        }
        if (saveInfo) {
            saveInfoDocument(index + "_count", Integer.toString(count));
        }
    }

    private void indexDocument(String id) throws IOException {
        final Request indexRequest = new Request("POST", "/" + index + "/" + type + "/" + id);
        indexRequest.setJsonEntity(Strings.toString(JsonXContent.contentBuilder().startObject().field("f", "v").endObject()));
        assertOK(client().performRequest(indexRequest));
    }

    private int countOfIndexedRandomDocuments() throws IOException {
        return Integer.parseInt(loadInfoDocument(index + "_count"));
    }

    private void saveInfoDocument(String id, String value) throws IOException {
        XContentBuilder infoDoc = JsonXContent.contentBuilder().startObject();
        infoDoc.field("value", value);
        infoDoc.endObject();
        // Only create the first version so we know how many documents are created when the index is first created
        Request request = new Request("PUT", "/info/" + type + "/" + id);
        request.addParameter("op_type", "create");
        request.setJsonEntity(Strings.toString(infoDoc));
        client().performRequest(request);
    }

    private String loadInfoDocument(String id) throws IOException {
        Request request = new Request("GET", "/info/_doc/" + id);
        request.addParameter("filter_path", "_source");
        String doc = toStr(client().performRequest(request));
        Matcher m = Pattern.compile("\"value\":\"(.+)\"").matcher(doc);
        assertTrue(doc, m.find());
        return m.group(1);
    }

    private void refresh() throws IOException {
        logger.debug("Refreshing [{}]", index);
        client().performRequest(new Request("POST", "/" + index + "/_refresh"));
    }

    private List<String> dataNodes(String index, RestClient client) throws IOException {
        Request request = new Request("GET", index + "/_stats");
        request.addParameter("level", "shards");
        Response response = client.performRequest(request);
        List<String> nodes = new ArrayList<>();
        List<Object> shardStats = ObjectPath.createFromResponse(response).evaluate("indices." + index + ".shards.0");
        for (Object shard : shardStats) {
            final String nodeId = ObjectPath.evaluate(shard, "routing.node");
            nodes.add(nodeId);
        }
        return nodes;
    }

    /**
     * Wait for an index to have green health, waiting longer than
     * {@link OpenSearchRestTestCase#ensureGreen}.
     */
    protected void ensureGreenLongWait(String index) throws IOException {
        Request request = new Request("GET", "/_cluster/health/" + index);
        request.addParameter("timeout", "2m");
        request.addParameter("wait_for_status", "green");
        request.addParameter("wait_for_no_relocating_shards", "true");
        request.addParameter("wait_for_events", "languid");
        request.addParameter("level", "shards");
        Map<String, Object> healthRsp = entityAsMap(client().performRequest(request));
        logger.info("health api response: {}", healthRsp);
        assertEquals("green", healthRsp.get("status"));
        assertFalse((Boolean) healthRsp.get("timed_out"));
    }

    public void testPeerRecoveryRetentionLeases() throws Exception {
        if (isRunningAgainstOldCluster()) {
            XContentBuilder settings = jsonBuilder();
            settings.startObject();
            {
                settings.startObject("settings");
                settings.field("number_of_shards", between(1, 5));
                settings.field("number_of_replicas", between(0, 1));
                if (randomBoolean() || getOldClusterVersion().before(LegacyESVersion.V_7_0_0)) {
                    // this is the default after v7.0.0, but is required before that
                    settings.field("soft_deletes.enabled", true);
                }
                settings.endObject();
            }
            settings.endObject();

            Request createIndex = new Request("PUT", "/" + index);
            createIndex.setJsonEntity(Strings.toString(settings));
            client().performRequest(createIndex);
        }
        ensureGreen(index);
        ensurePeerRecoveryRetentionLeasesRenewedAndSynced(index);
    }

    /**
     * Tests that with or without soft-deletes, we should perform an operation-based recovery if there were some
     * but not too many uncommitted documents (i.e., less than 10% of committed documents or the extra translog)
     * before we restart the cluster. This is important when we move from translog based to retention leases based
     * peer recoveries.
     */
    public void testOperationBasedRecovery() throws Exception {
        if (isRunningAgainstOldCluster()) {
            final Settings.Builder settings = Settings.builder()
                .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
                .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 1);
            if (minimumNodeVersion().before(Version.V_2_0_0)) {
                settings.put(IndexSettings.INDEX_SOFT_DELETES_SETTING.getKey(), randomBoolean());
            }
            createIndex(index, settings.build());
            ensureGreen(index);
            int committedDocs = randomIntBetween(100, 200);
            for (int i = 0; i < committedDocs; i++) {
                indexDocument(Integer.toString(i));
                if (rarely()) {
                    flush(index, randomBoolean());
                }
            }
            flush(index, true);
            ensurePeerRecoveryRetentionLeasesRenewedAndSynced(index);
            // less than 10% of the committed docs (see IndexSetting#FILE_BASED_RECOVERY_THRESHOLD_SETTING).
            int uncommittedDocs = randomIntBetween(0, (int) (committedDocs * 0.1));
            for (int i = 0; i < uncommittedDocs; i++) {
                final String id = Integer.toString(randomIntBetween(1, 100));
                indexDocument(id);
            }
        } else {
            ensureGreen(index);
            assertNoFileBasedRecovery(index, n -> true);
            ensurePeerRecoveryRetentionLeasesRenewedAndSynced(index);
        }
    }

    /**
     * Verifies that once all shard copies on the new version, we should turn off the translog retention for indices with soft-deletes.
     */
    public void testTurnOffTranslogRetentionAfterUpgraded() throws Exception {
        if (isRunningAgainstOldCluster()) {
            createIndex(index, Settings.builder()
                .put(IndexMetadata.INDEX_NUMBER_OF_SHARDS_SETTING.getKey(), 1)
                .put(IndexMetadata.INDEX_NUMBER_OF_REPLICAS_SETTING.getKey(), 1)
                .put(IndexSettings.INDEX_SOFT_DELETES_SETTING.getKey(), true).build());
            ensureGreen(index);
            int numDocs = randomIntBetween(10, 100);
            for (int i = 0; i < numDocs; i++) {
                indexDocument(Integer.toString(randomIntBetween(1, 100)));
                if (rarely()) {
                    flush(index, randomBoolean());
                }
            }
        } else {
            ensureGreen(index);
            flush(index, true);
            assertEmptyTranslog(index);
            ensurePeerRecoveryRetentionLeasesRenewedAndSynced(index);
        }
    }

    public void testResize() throws Exception {
        int numDocs;
        if (isRunningAgainstOldCluster()) {
            final Settings.Builder settings = Settings.builder()
                .put(IndexMetadata.INDEX_NUMBER_OF_SHARDS_SETTING.getKey(), 3)
                .put(IndexMetadata.INDEX_NUMBER_OF_REPLICAS_SETTING.getKey(), 1);
            if (minimumNodeVersion().before(Version.V_2_0_0) && randomBoolean()) {
                settings.put(IndexSettings.INDEX_SOFT_DELETES_SETTING.getKey(), false);
            }
            final String mappings = randomBoolean() ? "\"_source\": { \"enabled\": false}" : null;
            createIndex(index, settings.build(), mappings);
            numDocs = randomIntBetween(10, 1000);
            for (int i = 0; i < numDocs; i++) {
                indexDocument(Integer.toString(i));
                if (rarely()) {
                    flush(index, randomBoolean());
                }
            }
            saveInfoDocument("num_doc_" + index, Integer.toString(numDocs));
            ensureGreen(index);
        } else {
            ensureGreen(index);
            numDocs = Integer.parseInt(loadInfoDocument("num_doc_" + index));
            int moreDocs = randomIntBetween(0, 100);
            for (int i = 0; i < moreDocs; i++) {
                indexDocument(Integer.toString(numDocs + i));
                if (rarely()) {
                    flush(index, randomBoolean());
                }
            }
            Request updateSettingsRequest = new Request("PUT", "/" + index + "/_settings");
            updateSettingsRequest.setJsonEntity("{\"settings\": {\"index.blocks.write\": true}}");
            client().performRequest(updateSettingsRequest);
            {
                final String target = index + "_shrunken";
                Request shrinkRequest = new Request("PUT", "/" + index + "/_shrink/" + target);
                Settings.Builder settings = Settings.builder().put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1);
                if (randomBoolean()) {
                    settings.put(IndexSettings.INDEX_SOFT_DELETES_SETTING.getKey(), true);
                }
                shrinkRequest.setJsonEntity("{\"settings\":" + Strings.toString(settings.build()) + "}");
                client().performRequest(shrinkRequest);
                ensureGreenLongWait(target);
                assertNumHits(target, numDocs + moreDocs, 1);
            }
            {
                final String target = index + "_split";
                Settings.Builder settings = Settings.builder().put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 6);
                if (randomBoolean()) {
                    settings.put(IndexSettings.INDEX_SOFT_DELETES_SETTING.getKey(), true);
                }
                Request splitRequest = new Request("PUT", "/" + index + "/_split/" + target);
                splitRequest.setJsonEntity("{\"settings\":" + Strings.toString(settings.build()) + "}");
                client().performRequest(splitRequest);
                ensureGreenLongWait(target);
                assertNumHits(target, numDocs + moreDocs, 6);
            }
            {
                final String target = index + "_cloned";
                client().performRequest(new Request("PUT", "/" + index + "/_clone/" + target));
                ensureGreenLongWait(target);
                assertNumHits(target, numDocs + moreDocs, 3);
            }
        }
    }

    @SuppressWarnings("unchecked")
    public void testSystemIndexMetadataIsUpgraded() throws Exception {
        final String systemIndexWarning = "this request accesses system indices: [.tasks], but in a future major version, direct " +
            "access to system indices will be prevented by default";
        if (isRunningAgainstOldCluster()) {
            // create index
            Request createTestIndex = new Request("PUT", "/test_index_old");
            createTestIndex.setJsonEntity("{\"settings\": {\"index.number_of_replicas\": 0, \"index.number_of_shards\": 1}}");
            client().performRequest(createTestIndex);

            Request bulk = new Request("POST", "/_bulk");
            bulk.addParameter("refresh", "true");
            bulk.setJsonEntity("{\"index\": {\"_index\": \"test_index_old\"}}\n" + "{\"f1\": \"v1\", \"f2\": \"v2\"}\n");
            client().performRequest(bulk);

            // start a async reindex job
            Request reindex = new Request("POST", "/_reindex");
            reindex.setJsonEntity(
                "{\n" +
                    "  \"source\":{\n" +
                    "    \"index\":\"test_index_old\"\n" +
                    "  },\n" +
                    "  \"dest\":{\n" +
                    "    \"index\":\"test_index_reindex\"\n" +
                    "  }\n" +
                    "}");
            reindex.addParameter("wait_for_completion", "false");
            Map<String, Object> response = entityAsMap(client().performRequest(reindex));
            String taskId = (String) response.get("task");

            // wait for task
            Request getTask = new Request("GET", "/_tasks/" + taskId);
            getTask.addParameter("wait_for_completion", "true");
            client().performRequest(getTask);

            // make sure .tasks index exists
            Request getTasksIndex = new Request("GET", "/.tasks");
            getTasksIndex.addParameter("allow_no_indices", "false");
            if (getOldClusterVersion().before(LegacyESVersion.V_7_0_0)) {
                getTasksIndex.addParameter("include_type_name", "false");
            }

            getTasksIndex.setOptions(expectVersionSpecificWarnings(v -> {
                v.current(systemIndexWarning);
                v.compatible(systemIndexWarning);
            }));
            assertBusy(() -> {
                try {
                    assertThat(client().performRequest(getTasksIndex).getStatusLine().getStatusCode(), is(200));
                } catch (ResponseException e) {
                    throw new AssertionError(".tasks index does not exist yet");
                }
            });

            // If we are on 7.x create an alias that includes both a system index and a non-system index so we can be sure it gets
            // upgraded properly. If we're already on 8.x, skip this part of the test.
            if (minimumNodeVersion().before(SYSTEM_INDEX_ENFORCEMENT_VERSION)) {
                // Create an alias to make sure it gets upgraded properly
                Request putAliasRequest = new Request("POST", "/_aliases");
                putAliasRequest.setJsonEntity("{\n" +
                    "  \"actions\": [\n" +
                    "    {\"add\":  {\"index\":  \".tasks\", \"alias\": \"test-system-alias\"}},\n" +
                    "    {\"add\":  {\"index\":  \"test_index_reindex\", \"alias\": \"test-system-alias\"}}\n" +
                    "  ]\n" +
                    "}");
                assertThat(client().performRequest(putAliasRequest).getStatusLine().getStatusCode(), is(200));
            }
        } else {
            assertBusy(() -> {
                Request clusterStateRequest = new Request("GET", "/_cluster/state/metadata");
                Map<String, Object> indices = new XContentTestUtils.JsonMapView(entityAsMap(client().performRequest(clusterStateRequest)))
                    .get("metadata.indices");

                // Make sure our non-system index is still non-system
                assertThat(new XContentTestUtils.JsonMapView(indices).get("test_index_old.system"), is(false));

                // Can't get the .tasks index via JsonMapView because it splits on `.`
                assertThat(indices, hasKey(".tasks"));
                XContentTestUtils.JsonMapView tasksIndex = new XContentTestUtils.JsonMapView((Map<String, Object>) indices.get(".tasks"));
                assertThat(tasksIndex.get("system"), is(true));

                // If .tasks was created in a 7.x version, it should have an alias on it that we need to make sure got upgraded properly.
                final String tasksCreatedVersionString = tasksIndex.get("settings.index.version.created");
                assertThat(tasksCreatedVersionString, notNullValue());
                final Version tasksCreatedVersion = Version.fromId(Integer.parseInt(tasksCreatedVersionString));
                if (tasksCreatedVersion.before(SYSTEM_INDEX_ENFORCEMENT_VERSION)) {
                    // Verify that the alias survived the upgrade
                    Request getAliasRequest = new Request("GET", "/_alias/test-system-alias");
                    getAliasRequest.setOptions(expectVersionSpecificWarnings(v -> {
                        v.current(systemIndexWarning);
                        v.compatible(systemIndexWarning);
                    }));
                    Map<String, Object> aliasResponse = entityAsMap(client().performRequest(getAliasRequest));
                    assertThat(aliasResponse, hasKey(".tasks"));
                    assertThat(aliasResponse, hasKey("test_index_reindex"));
                }
            });
        }
    }

    public void testEnableSoftDeletesOnRestore() throws Exception {
        assumeTrue("soft deletes must be enabled on 2.0+", getOldClusterVersion().before(Version.V_2_0_0));
        final String snapshot = "snapshot-" + index;
        if (isRunningAgainstOldCluster()) {
            final Settings.Builder settings = Settings.builder()
                .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
                .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 1);
            settings.put(IndexSettings.INDEX_SOFT_DELETES_SETTING.getKey(), false);
            createIndex(index, settings.build());
            ensureGreen(index);
            int numDocs = randomIntBetween(0, 100);
            indexRandomDocuments(numDocs, true, true, randomBoolean(), i -> jsonBuilder().startObject().field("field", "value").endObject());
            // create repo
            XContentBuilder repoConfig = JsonXContent.contentBuilder().startObject();
            {
                repoConfig.field("type", "fs");
                repoConfig.startObject("settings");
                {
                    repoConfig.field("compress", randomBoolean());
                    repoConfig.field("location", System.getProperty("tests.path.repo"));
                }
                repoConfig.endObject();
            }
            repoConfig.endObject();
            Request createRepoRequest = new Request("PUT", "/_snapshot/repo");
            createRepoRequest.setJsonEntity(Strings.toString(repoConfig));
            client().performRequest(createRepoRequest);
            // create snapshot
            Request createSnapshot = new Request("PUT", "/_snapshot/repo/" + snapshot);
            createSnapshot.addParameter("wait_for_completion", "true");
            createSnapshot.setJsonEntity("{\"indices\": \"" + index + "\"}");
            client().performRequest(createSnapshot);
        } else {
            String restoredIndex = "restored-" + index;
            // Restore
            XContentBuilder restoreCommand = JsonXContent.contentBuilder().startObject();
            restoreCommand.field("indices", index);
            restoreCommand.field("rename_pattern", index);
            restoreCommand.field("rename_replacement", restoredIndex);
            restoreCommand.startObject("index_settings");
            {
                restoreCommand.field("index.soft_deletes.enabled", true);
            }
            restoreCommand.endObject();
            restoreCommand.endObject();
            Request restoreRequest = new Request("POST", "/_snapshot/repo/" + snapshot + "/_restore");
            restoreRequest.addParameter("wait_for_completion", "true");
            restoreRequest.setJsonEntity(Strings.toString(restoreCommand));
            client().performRequest(restoreRequest);
            ensureGreen(restoredIndex);
            int numDocs = countOfIndexedRandomDocuments();
            assertTotalHits(numDocs, entityAsMap(client().performRequest(new Request("GET", "/" + restoredIndex + "/_search"))));
        }
    }

    public void testForbidDisableSoftDeletesOnRestore() throws Exception {
        final String snapshot = "snapshot-" + index;
        if (isRunningAgainstOldCluster()) {
            final Settings.Builder settings = Settings.builder()
                .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
                .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 1)
                .put(IndexSettings.INDEX_SOFT_DELETES_SETTING.getKey(), true);
            createIndex(index, settings.build());
            ensureGreen(index);
            int numDocs = randomIntBetween(0, 100);
            indexRandomDocuments(numDocs, true, true, randomBoolean(), i -> jsonBuilder().startObject().field("field", "value").endObject());
            // create repo
            XContentBuilder repoConfig = JsonXContent.contentBuilder().startObject();
            {
                repoConfig.field("type", "fs");
                repoConfig.startObject("settings");
                {
                    repoConfig.field("compress", randomBoolean());
                    repoConfig.field("location", System.getProperty("tests.path.repo"));
                }
                repoConfig.endObject();
            }
            repoConfig.endObject();
            Request createRepoRequest = new Request("PUT", "/_snapshot/repo");
            createRepoRequest.setJsonEntity(Strings.toString(repoConfig));
            client().performRequest(createRepoRequest);
            // create snapshot
            Request createSnapshot = new Request("PUT", "/_snapshot/repo/" + snapshot);
            createSnapshot.addParameter("wait_for_completion", "true");
            createSnapshot.setJsonEntity("{\"indices\": \"" + index + "\"}");
            client().performRequest(createSnapshot);
        } else {
            // Restore
            XContentBuilder restoreCommand = JsonXContent.contentBuilder().startObject();
            restoreCommand.field("indices", index);
            restoreCommand.field("rename_pattern", index);
            restoreCommand.field("rename_replacement", "restored-" + index);
            restoreCommand.startObject("index_settings");
            {
                restoreCommand.field("index.soft_deletes.enabled", false);
            }
            restoreCommand.endObject();
            restoreCommand.endObject();
            Request restoreRequest = new Request("POST", "/_snapshot/repo/" + snapshot + "/_restore");
            restoreRequest.addParameter("wait_for_completion", "true");
            restoreRequest.setJsonEntity(Strings.toString(restoreCommand));
            final ResponseException error = expectThrows(ResponseException.class, () -> client().performRequest(restoreRequest));
            assertThat(error.getMessage(), containsString("cannot disable setting [index.soft_deletes.enabled] on restore"));
        }
    }

    public static void assertNumHits(String index, int numHits, int totalShards) throws IOException {
        Map<String, Object> resp = entityAsMap(client().performRequest(new Request("GET", "/" + index + "/_search")));
        assertNoFailures(resp);
        assertThat(XContentMapValues.extractValue("_shards.total", resp), equalTo(totalShards));
        assertThat(XContentMapValues.extractValue("_shards.successful", resp), equalTo(totalShards));
        assertThat(extractTotalHits(resp), equalTo(numHits));
    }

}
